Field of the Invention
The present invention relates to a retainer used in a rolling bearing and a method of manufacturing such retainer and, more particularly, to the technology of making such retainer by means of an insert molding of a core member with resinous material.
Description of Related Art
As a resin made retainer used in the bearing, that which is formed by the use of an insert molding applied to the resinous material and that which is formed by the insert molding of the resinous material together with an insert member in the form of, for example, an iron plate are available. (In this connection, reference is made to the patent documents 1 and 2 listed below.) Of them the retainer shown in FIG. 20 of the accompanying drawings is a resin made, crown shaped retainer (also referred to as “resin made snap cage”) in which an insert member 51 is provided at a bottom face 50 on the rear side of pockets Pt. On the other hand, the retainer shown in FIG. 21 of the accompanying drawings is a crown shaped retainer having its side face provided with an insert member 52.
Also, even in the bearing for use with the precision machinery, a plurality of cylindrical rollers having a relatively uniform outer diametric dimension have hitherto been assembled into a single row or multi-row cylindrical roller bearing and the use is made therein of a retainer for retaining those cylindrical rollers in equally circumferentially spaced relation to each other. (In this respect, see the patent document 3 listed below.) The retainer largely employed in the multi-low cylindrical roller bearing is in the form of a resin made retainer. For a high speed rotation use, the use of a material having a high rigidity, such as, for example, a polyether ether ketone resin (PEEK) or a polyphenylene sulfide resin (PPS) is often made so that the retainer can withstand the centrifugal force acting thereon.